1. Field of the Invention
This invention relates to optical telemetry systems.
2. Summary of the Prior Art
Conventional telemetry systems are based on a principle which involves formation of an image of an object by the superposition of two images of the same object derived from two different optical paths each path comprising at least one reflection on a first mirror rotatable about an axis, the two axes being parallel to one another. In such systems, a bi-univocal relationship exists between the distance to be measured and the angular orientation of the mirrors. Knowledge of this orientation, at the instant of when the images are precisely superposed, is thus equivalent to the knowledge of the distance to be measured. When the telemetry is to be carried out over short distances, it is, moreover well known to employ identical path lengths for the two optical paths, thus enabling the images to have the same outline, which is essential to provide perfect superposition and thus to achieve precise measurement.
The invention relates more particularly to a system of the kind hereinbefore outlined in which the observation of the image produced is carried out by means of a video camera. For numerous industrial applications, it is necessary that the optical system of such a video camera should have a high magnification, therefore a reduced angular field of vision. The use of a collimating system with a larger angular field of vision also provided by video camera, is necessary so as to facilitate exploitation by providing, in addition, an image of the surroundings.